Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/36—Selection of substances as active materials, active masses, active liquids
  • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
  • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
  • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
  • C01G45/00—Compounds of manganese
  • C01G45/12—Manganates manganites or permanganates
  • C01G45/1221—Manganates or manganites with a manganese oxidation state of Mn(III), Mn(IV) or mixtures thereof
  • C01G45/1242—Manganates or manganites with a manganese oxidation state of Mn(III), Mn(IV) or mixtures thereof of the type [Mn2O4]-, e.g. LiMn2O4, Li[MxMn2-x]O4
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
  • C01G51/00—Compounds of cobalt
  • C01G51/40—Cobaltates
  • C01G51/42—Cobaltates containing alkali metals, e.g. LiCoO2
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
  • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
  • H01M4/139—Processes of manufacture
  • H01M4/1391—Processes of manufacture of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/36—Selection of substances as active materials, active masses, active liquids
  • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
  • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/36—Selection of substances as active materials, active masses, active liquids
  • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
  • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
  • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2006/00—Physical properties of inorganic compounds
  • C01P2006/40—Electric properties
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/10—Energy storage using batteries

Definitions

• This invention relates to a method for the preparation of fine powders and/or thick films of lithium containing ternary oxides. M ore specifically, the present invention relates to the low temperature synthesis of LiMn 2 O and LiCo ⁇ 2 which are intercalable compounds of interest for secondary batteries.
• the lithium containing ternary oxides have been prepared by mixing the carbonates and oxides of the constituent components and heating the mixture at temperatures within the range of 700-800°C .
• the resultant compositions have proven satisfactory for most purposes, studies have revealed that the high temperatures employed in the synthesis thereof often adversely affect the electrochemical properties of the compositions.
• the lithium-based intercalation compounds of LiMn 2 0 and LiCo0 2 have sparked widespread interest for use in the next generation of rocking chair batteries, workers in the art have focused their attention upon the development of alternate techniques for obtaining these compositions. Specifically, new routes have been sought to attain a m ethod yielding materials of controlled m orphology and grain size to improve battery behavior.
• this end has been attained by a novel processing sequence wherein a weak acetate ligand in combination with a hydroxide solution to maintain a balanced pH permits the formation of fine particles of a mixed hydroxide-acetate composition. More specifically, there is described herein a method for the synthesis of LiMn 2 O and LiCoO 2 phases by a novel sol-gel process involving the condensation of oxide networks from solution precursors. Briefly, this involves hydrolyzing manganese or cobalt acetates or other carboxylates in an aqueous solution , the hydrolysis being promoted by the addition of the hydroxides of lithium and ammonium which control the pH of the solution.
• Hydrolysis is initiated by the addition of lithium hydroxide and completed by the use of a base that can be removed thermally.
• This base may be selected from among any organic base or ammonium hydroxide which is preferred for use herein .
• This low temperature process yield a gel-like product which may be used to prepare either bulk or thick films of LiMn O 4 or LiCoO 2 which evidence electrochemical properties suitable for use in rocking chair batteries.
• FIG. 1 is a graphical representation on coordinates of x in
• Li x Mn 2 O 4 against voltage in volts showing the cycling characteristics between 4.5 and 3.5 volts at a current density of 600 ⁇ A/cm 2 for powder compositions of lithium manganese oxide annealed at temperatures from 300-800°C used initially as the positive electrode in a secondary lithium battery in which lithium metal is used as the negative electrode;
• FIG . 2 is a graphical representation on coordinates of x in Li x Mn 2 O for x greater than one but less than 2 against voltage in volts showing the cycling characteristics between 3.5 and 2.2 volts at a current density of 400 ⁇ A/cm for compositions of lithium manganese oxide powders annealed at temperatures from 300-800°C when used as positive electrodes in secondary lithium batteries;
• FIG . 3 is a graphical representation on coordinates of x in
• Li x Mn 2 O against voltage in volts showing typical composite cycling behavior over a potential range of 4.5-2.2 volts at a current density of 800 ⁇ A/cm for cells using LiMn 2 O 4 sythesized at 400°C as the positive electrode in secondary lithium batteries;
• FIG . 4 is a graphical representation on coordinates of x in
• Li x Mn 2 O against voltage in volts showing the cycling behavior between 4.5 and 3.5 volts at a current density of 40 ⁇ A/cm for a cell using a 10 micron LiMn O 4 thick film prepared by dipping as the positive electrode in a secondary lithium battery.
• the initial step in the practice of the present invention involves preparing an acetate precursor for the ternary oxide. This end is effected by admixing, with rapid stirring, an acetate of manganese or cobalt and the hydroxides of lithium and ammonium in an amount sufficient to yield the stoichiometric phase of the ternary oxide.
• the ammonium hydroxide is employed primarily for the purpose of adjusting the pH to a value of approximately 7, the point at which a controlled precipitation occurs.
• the required amount of ammonium is defined by the sum of hydroxyl groups from lithium hydroxide and from ammonium hydroxide equal to the normality of the transition metal cation , Mn , or for Co in LiCoO 2 .
• the gelatinous precipitate so formed is dried thermally at a temperature ranging from 60°C — 150°C , the specific temperature chosen being dependent upon the composition and desired use thereof.
• heating the manganese composition at a temperature of 90°C permits formation of a viscous solution which can be deposited upon a suitable substrate by spin coating which permits subsequent synthesis of LiMn O 4 thick films.
• Heating of the gelatinous precipitate at the higher temperatures (150° C) results in the formation of a xerogel of small grain size.
• the resultant xerogels of manganese and cobalt are heated to a temperature within the range of 200-500°C to remove the acetate.
• Compositions selected for use included a 0.8 M/l solution of manganese acetate, lithium hydroxide ( 1 M/l) and ammonium hydroxide (3 M/l) .
• the manganese and lithium solutions were employed in stoichiometric amounts to yield the required phase of LiMn 2 0 4 .
• the ammonium hydroxide was employed in an amount sufficient to furnish 2 hydroxyl ions per metal ion .
• the hydroxides were quickly added to the manganese acetate solution with violent stirring, so resulting in the instantaneous formation of a gelatinous precipitate, the manganese solution being protected against oxygen to avoid formation of Mn + 3 .
• the precipitate was then dried by heating up to 150 C C to yield a homogeneous xerogel in which the lithium and manganese ions were well mixed . Finally, the dried precipitate was annealed at a temperature within the range of 200-400°C to yield the acetate free LiMn 2 0 4 phase which comprised grains or crystallites ranging in size between 0.3 ⁇ m and 1 ⁇ m .
• the resulting LiMn 2 O 4 powders prepared at 300°C and 400°C were then compared with similar powders prepared at temperatures of 500, 600, and 800°C and their intercalation properties assessed . This end was attained using swagelock test cells that were assembled in a helium dry-box .
• LiMn 2 O 4 powder Approximately 20 mg of LiMn 2 O 4 powder was mixed with 10% carbon black, pressed into a pellet and used as the positive electrode with lithium as the negative electrode . Both electrodes were separated by a porous glass filter soaked in an electrolyte prepared by dissolving 1 M /l LiC10 4 and 1M 12-crown-4 ether in propylene carbonate. Cycling data was then obtained and plotted in graphical form .
• FIG . 1 there is shown a graphical representation on coordinates of Li x Mn 2 O 4 against voltage in volts showing the cycling data over a range of potential from 4.5-3.5 volts for the foregoing compositions annealed at temperatures from 300-800°C at a current density of 600 ⁇ A/cm 2 .
• the assembled cell is first charged to remove the Li ions within Li x Mn 2 0 4 , so that the cathode then becomes the open structure spinel ⁇ -Mn 2 0 4 .
• the assembled cells containing Li x Mn 2 O 4 powders were automatically tested, equivalently charged and discharged up to four cycles at a constant current while potential was monitored as a function of time.
• a review of FIG . 1 reveals that the cycling data was in the range of potential of 4.5-3.5 volts which corresponds to the first lithium intercalation plateau for intercalation of 1 Li into ⁇ -Mn O 4 , and over the range of potential of 3.5-2.2 volts (shown on the sam e coordinates in FIG . 2) which corresponds to the second lithium intercalation plateau into LiMn 2 O 4 to give Li 2 Mn 2 O 4 .
• FIG. 3 there is shown a graphical representation on coordinates of Li x Mn 2 O 4 content against voltage in volts showing the cycling characteristics between 4.5 and 2 volts, covering both plateaus.
• FIG. 4 there is shown a graphical representation on coordinates of Li x Mn 2 O content (thick film) against voltage in volts showing cycling behavior over the range of 4.5-3.0 volts at 400 ⁇ A/cm 2 .
• the electrode was prepared by forming a 10 ⁇ m thick film of Li x Mn 2 0 4 by dipping a stainless steel substrate into a viscous acetate aqueous solution prepared as described above and then fired for 16 hours at 600°C .
• the cycling data are similar to that shown for the bulk material.

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• Chemical & Material Sciences (AREA)
• Inorganic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Battery Electrode And Active Subsutance (AREA)
• Inorganic Compounds Of Heavy Metals (AREA)

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Cited By (8)

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Citations (11)

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• 1991
  • 1991-04-23 US US07/690,080 patent/US5135732A/en not_active Expired - Lifetime
• 1992
  • 1992-03-05 WO PCT/US1992/001678 patent/WO1992018425A1/en active IP Right Grant
  • 1992-03-05 JP JP4506780A patent/JP2649440B2/ja not_active Expired - Lifetime
  • 1992-03-05 EP EP92907079A patent/EP0581785B1/en not_active Expired - Lifetime
  • 1992-03-05 DE DE69206793T patent/DE69206793T2/de not_active Expired - Fee Related
  • 1992-03-05 CA CA002109103A patent/CA2109103C/en not_active Expired - Fee Related

Patent Citations (11)

Non-Patent Citations (4)

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